According to the regulation of U.S. code for standard pressure gauge (ANSI-SP9), the commercially available digital pressure gauge requires calibration after 10,000 times of operation to ensure the accuracy thereof.
Moreover, according to the regulation of European code (EN1060-3: 1997 code 9.2a), the digital pressure gauge requires calibration requires calibration after 2 years of operation to ensure the accuracy thereof.
However, the current digital pressure gauge is generally provided the function of detecting operation times and duration. Therefore, the users do not have sufficient information for their digital pressure gauges and the accuracy of the digital pressure gauge cannot be ensured.